The present invention relates to an optical switch for changing over connections of optical signals transmitted over a plurality of optical fibers and also relates to an optical switch system using the optical switches.
In optical communications using optical fiber, an N×N optical switch is used which receives at its N input ports optical signals arriving on optical fiber, can couple any one of incoming optical signals to one of the N output ports, and this optical switch can change over connections.
In a general structure of the so-called 3-dimensional (or space type) optical matrix switch, a set of a collimator array and a micro mirror array is provided on each of the input and output sides, the collimator array includes a plurality of collimators for emitting an optical beam carrying optical signals into a free-space micro optical system and the micro mirror array includes a plurality of movable micro mirrors normally manufactured by using MEMS (Micro Electro-mechanical System) technology. The beam emitted from a collimator on the input side is controlled in its direction by two micro mirrors and led to an arbitrary collimator on the output side.
With regard to the structure of an optical switch with a fiber array and an MEMS mirror array, and with a bounce-back mirror placed at a midway point of the optical path, an example is disclosed in JP-A-2002-169107, which is aimed at facilitating the mounting of optical components by using a simplified structure. A structure using a roof-type retro-reflector mirror is disclosed in “Development of a Small Easy-to-Assemble 3-dimensional MEMS Optical Switch Fabric” in B-12-4 (p. 444) of the prearranged papers for 2002 Institute of Electronics, Information and Communication Engineers—Communication Society Convention.